Method and apparatus for occluding a physiological opening

ABSTRACT

A method and apparatus for suture-less placement of an occluding patch in which release of the device can be accelerated. In one embodiment, an inactive form of an adhesive is applied on the area of the patch that will come into contact with cardiac tissue; this allows for the introduction and necessary manipulation of the catheter system until activation of the adhesive occurs. In accordance with one aspect of the invention, the adhesive properties of certain polymeric materials are relied upon rather than their ability to cure or harden into a specific shape. In another embodiment, the patch is immediately released utilizing a detaching mechanism on the balloon or the balloon catheter which supports the patch; the patch along with the inflated balloon remain on the cardiac structure occluding the opening.

RELATED APPLICATION DATA

This application claims the priority of prior provisional U.S. patentapplication Ser. No. 61/270,455 filed on Jul. 9, 2009, which applicationis hereby incorporated by reference herein in its entirety.

FIELD OF THE INVENTION

This invention relates generally to cardiovascular devices, intended toocclude circulatory communications that may be or may become detrimentalto patient health. More specifically, this invention encompassesaccelerated release methods for an occlusion methodology involvingsutureless delivery of an occlusion patch to a physiological opening.

BACKGROUND OF THE INVENTION

Compromised health may be caused by cardiovascular structures thatadversely affect the proper flow of blood. Such structures may beabnormalities that affect a relatively small subset of the population,and others may be common and not normally pathogenic, yet become so dueto extrinsic causes. Examples of the former are congenital heart defectsincluding Atrial Septal Defect (ASD), Ventricular Septal Defect (VSD),and Patent Ductus Arteriosus (PDA), and examples of the latter arenormal cardiac structures such as Patent Foramen Ovale (PFO) and LeftAtrial Appendage (LAA). The above mentioned structures are generallycharacterized by a hole or opening, which allows for fluid communicationbetween cardiac chambers and/or blood vessels.

Congenital heart defects can cause an abnormal distribution ofcardiovascular pressures and the dilution of oxygenated blood, which cansignificantly reduce cardiac pumping efficiency. Normal cardiacstructures can sometimes become pathogenic by functioning as a locationof blood clot formation, as in the LAA, or as a path by which bloodclots can travel to the brain, as in PFO. Additionally, modifications tocardiovascular structures, which can cause anomalous blood flow, may beintentionally created by a physician in order to accommodate a certainprocedure or to elicit some therapeutic effect. An example of this isthe creation of a hole in the cardiac wall, in order to insert cathetersand have direct access to cardiac structures such as valves. Onetreatment option for such cardiovascular structures is to occlude thecommunication using a surgically or percutaneously implanted device.Patents have been issued for several such devices including U.S. Pat.No. 3,874.388 to King et al., U.S. Pat. No. 4,917,089 to Sideris, andU.S. Pat. No. 5,725,552 to Kotula et al. Although these patents vary inmany ways, their common attribute is that they include the concept of ametallic frame, intended to provide permanent support that maintains thedevice on the cardiac structure. Although metallic occlusive devices arewidely used, they carry certain risks including wire fractures,perforations, and potential leaching of toxic materials.

Devices containing no metallic materials can potentially eliminate someof these risks. Non-metallic occlusive devices have been proposed in theprior art, including: U.S. Pat. No. 5,192,301 to Kamiya et al., whichappears to describe a deformable plug made from a shape memory polymer;U.S. Pat. No. 5,634,936 to Linden et al. which appears to describe adevice that includes a “self-hardening” polymeric material; U.S. Pat.No. 6,238,416 to Sideris, which appears to describe a balloondeliverable polymeric device; and U.S. patent application Ser. No.11/728,906 to Opolski et al. describing a device using a polymeric wireframe. To the inventors' knowledge, only one of these patents covers adevice that is in commercial use; this is U.S. Pat. No. 6,238,416 toSideris, which patent is hereby incorporated by reference herein in itsentirety.

The Sideris '416 patent describes a method of suture-less patchplacement to correct a physiological opening in the form of a heartdefect comprising a hole. The patch is first attached to a deflatedballoon which is placed distally to the hole using special deliverycatheters. The balloon is inflated with fluid and the patch ispositioned upon the hole. After a specifiedcoagulation/endothelialization period of time, the balloon is deflatedand removed through a small hole in the patch, leaving the patch toocclude the defect. Practically, the coagulation/endothelializationprocess serves to attach/adhere the patch onto the cardiac tissue. Thisprocess requires an extended period of time, which can be dependent onthe patch material. The extended period of time required for completionof this process makes the procedure inconvenient compared with otherocclusive techniques and devices.

SUMMARY OF THE INVENTION

In view of the foregoing and other considerations, the present inventionrelates to a method and apparatus for suture-less placement of anoccluding patch in which release of the device can be accelerated. Theimportance and potential of the invention is significant, since thedefects are corrected conveniently on an outpatient basis and potentialcomplications such as thrombosis or infection are diminished.

Attachment of the patch and/or device release can be accelerated by twomethods. In one embodiment, an inactive form of an adhesive is appliedon the area of the patch that will come into contact with cardiactissue; this allows for the introduction and necessary manipulation ofthe catheter system until activation of the adhesive occurs. In anotherembodiment, the patch is immediately released utilizing a detachingmechanism on the balloon or the balloon catheter which supports thepatch; the patch along with the inflated balloon remain on the cardiacstructure occluding the opening.; The patch and balloon are immobilized,either by the shape (double disk, spherical, etc.) and fit of theballoon in the opening, or by a thread or an anchoring tube which isconnected to the occluder and can be manipulated from the percutaneousentry point (usually the groin). All materials used for this device maybe bio-degradable and are progressively metabolized or eroded, and inthe case of the patch, replaced by natural tissue.

In accordance with one aspect of the invention, the adhesive propertiesof certain polymeric materials are relied upon rather than their abilityto cure or harden into a specific shape. Indeed, the use of polymericself-hardening materials has been described in U.S. Pat. No. 5,634,936;these materials can be delivered by a catheter to the area of the defectand hardened in situ by change the pH or ionic concentration, exposureto light or thermal energy.

Those of ordinary skill in the art having the benefit of the presentdisclosure will appreciate that accelerated patch attachment using anadhesive or immediate patch release using temporary support of abio-absorbable thread can find several other applications, including butnot limited to heart valves, internal vascular work and even coronaryartery surgery. Furthermore, surgeons could use the suture-lesstechnique to avoid suture related injury during surgery.

BRIEF DESCRIPTION OF THE DRAWINGS

The present invention is best understood with reference to the followingdetailed description of embodiments of the invention when read inconjunction with the attached drawings, in which like numerals refer tolike elements, and in which:

FIG. 1 is a side view of in introduction assembly for delivery andplacement of an occlusion device (patch) into a physiological opening,with adhesive placed on a proximal portion of the patch prior toimplantation;

FIG. 2 is a side view of in introduction assembly for delivery andplacement of an occlusion device (patch) into a physiological opening,with adhesive placed on a distal portion of the patch prior toimplantation;

FIG. 3 is a side view of the introduction assembly of FIG. 1 with aballoon mounted patch inserted into a short by-pass sheath; the proximalend of the patch extends outside of the short by-pass sheath and iscoated by the inactive adhesive;

FIG. 4 is a side view of the introduction assembly of FIG. 2 with aballoon mounted patch inserted into a short by-pass sheath; the distalend of the patch extends outside of the short by-pass sheath and iscoated by the inactive adhesive;

FIG. 5 is a side cross-sectional view of a correctly positioned andinflated patch, where the adhesive is coming into contact with thecardiovascular opening;

FIG. 6 is a side cross-sectional view of an ASD that has been coated byan initiator;

FIG. 7 is a side cross-sectional view of a correctly positioned andinflated patch being irradiated from inside the balloon;

FIG. 8 is a side view of an introduction assembly in accordance with oneembodiment of the invention prior to implantation.

FIG. 9 is a side cross-sectional view of an introduction assemblypositioned and inflated after the balloon catheter has been separatedinto its two components; and

FIG. 10 is a perspective view of an apparatus used in one embodiment ofthe invention to circumvent the suturing procedure.

DETAILED DESCRIPTION OF PREFERRED EMBODIMENTS OF THE INVENTION

In the disclosure that follows, in the interest of clarity, not allfeatures of actual implementations are described. It will of course beappreciated that in the development of any such actual implementation,as in any such project, numerous engineering and technical decisionsmust be made to achieve the developers' specific goals and subgoals(e.g., compliance with system and technical constraints), which willvary from one implementation to another. Moreover, attention willnecessarily be paid to proper medical and engineering practices for theenvironment in question. It will be appreciated that such developmentefforts might be complex and time-consuming, outside the knowledge baseof typical laymen, but would nevertheless be a routine undertaking forthose of ordinary skill in the relevant fields.

The present invention encompasses methods for accelerated attachmentand/or release of an occlusive device placed at the site of aphysiological opening, especially but not solely for applications in thecardiovascular field. The implantation procedure of one such occlusivedevice is described in detail in our previous U.S. Pat. No. 6,238,416(previously incorporated by reference herein) and as such will only bedescribed herein to the extent that it is necessary to illustrate theaccelerated attachment/release aspects of the present invention.

Method I

In accordance with one embodiment of the invention, acceleratedattachment of an occlusive patch can be achieved by the application ofan inactive form of an adhesive onto the patch prior to implantation.The adhesive can be polyethylene glycol based with end/side groups thatcan react with each other and the surrounding tissue to form strongchemical bonds. One adhesive believed to be suitable for the purposes ofthe invention is the commercially available product COSEAL® surgicalsealant, distributed by Baxter, Deerfield, Ill. More generally, theadhesive can take the form of a liquid, gel, or solid and may bechemically or mechanically bound to the patch. Said adhesive may beapplied onto the patch, either as part of the manufacturing process,directly before implantation, or during implantation.

In one embodiment, the adhesive is placed on the entire patch or on aselected portion of the patch, whichever is best suited for maximalapposition to the specific cardiovascular opening. Once the device ispositioned correctly in the appropriate physiological opening, theadhesive may be activated directly by several methods including pHchanges of the surrounding blood/tissue, temperature changes induced bythe normal body temperature or from input of thermal energy, and inputof electromagnetic energy including, but not limited to the UV, visible,and IR spectrums.

In an alternative embodiment of the invention, the adhesive may beactivated indirectly by a biocompatible initiator that is itselfactivated by the above mentioned methods. It is contemplated that suchan initiator may be injected into the blood stream around the defectbefore or during device implantation, in a way that adequately coats thesurface of the defect and/or the device. The initiator may also beapplied directly onto the patch prior to implantation.

In one embodiment, a two stage adhesive is used with a transition thatis sensitive to pH. Referring to FIG. 1, the adhesive 1, in its firststage, is applied to all or to a portion of the patch 2. The patch 2,which is mounted on a balloon catheter 3, is placed into a short by-passsheath 4. Any excessive adhesive material is wiped out by introductioninto the by-pass sheath. In one embodiment, the balloon-mounted patchcan be placed in the short by-pass sheath prior to application of theadhesive. A portion of the patch can be made to extend outside of theby-pass sheath and can then be coated with the inactive adhesive. It isthen pushed or pulled completely into the by-pass sheath, wiping awayany excessive adhesive material. Subsequently the balloon mounted patchis introduced through the hemostat valve of a long sheath, which isalready implanted in the patient, and is advanced to the appropriatephysiological opening. Activation occurs automatically due to the slightalkalinity of blood, but the reaction rate is slow enough to allow fordevice manipulation, balloon inflation, and placement.

In another embodiment, referring to FIG. 6, an initiator 5 that isactivated by electromagnetic radiation of a certain frequency isinjected near the physiological opening intended for occlusion. Theprocess effectively coats the opening with the initiator. The inactiveadhesive is then applied to all or to a portion of the patch and thedevice is placed into a short by-pass sheath. Any excessive adhesivematerial is wiped out by introduction into the by-pass sheath. Anadhesive can be applied as described with reference to the previousembodiment. Subsequently the balloon mounted patch is introduced throughthe hemostat valve of a long sheath, which is already implanted in thepatient, and is advanced to the appropriate physiological opening. Theballoon is inflated and the device is positioned appropriately toocclude the physiological opening. Electromagnetic radiation 6 isdelivered to the initiator through an optical fiber 7 that ends in adiffusing tip 8. The optical fiber may be advanced to the physiologicalopening through the balloon catheter to the balloon and irradiation maybe carried out from inside the balloon assuming that the balloon andinflating solution do not absorb the radiation. Alternatively, theoptical fiber may be advanced to the physiological opening independentlyand irradiation may be carried out from outside the balloon. Theelectromagnetic radiation may be, for example, in the ultraviolet (UV),visible, or infrared spectrums.

In yet another embodiment, an initiator that is activated byelectromagnetic radiation of a certain frequency is mixed with theinactive adhesive la. The mixture is then applied to all or to a portionof the patch and the device is placed into a short by-pass sheath. Anyexcessive mixture material is wiped out by introduction into the by-passsheath. An adhesive can be applied as described above. Subsequently theballoon mounted patch is introduced through the hemostat valve of a longsheath, which is already implanted in the patient, and is advanced tothe appropriate physiological opening. The balloon is inflated and thedevice is positioned appropriately to occlude the physiological opening.Electromagnetic radiation can then be delivered to the initiator by themethods presented in the previous embodiment.

Method II

In accordance with an alternative embodiment of the invention,accelerated release of the occlusive device without acceleratedattachment of the patch can be achieved by incorporating a detachmentmechanism into the balloon catheter. Such a mechanism allows forseparation of the inflated balloon from the catheter shaft after correctpositioning and inflation of the device. Both the balloon and thesurrounding patch then remain, occluding the defect, while the remainingmaterials are extracted. The balloon provides adequate support for along enough period of time in order for the patch to become attached tothe cardiac tissue through the normal coagulation/endothelializationprocess. Once the supporting function of the balloon is no longernecessary, it is deflated actively or passively in order for the devicevolume to be reduced to the size that is necessary for effectiveocclusion. The balloon may be made from synthetic or natural materialsthat are either bio-degradable or bio-stable, as would be apparent tothose of ordinary skill in the art. Additionally, the balloon may becompliant or non-compliant and may be formed into a regular shape(sphere, disk, etc.) or an organic shape in order to more appropriatelyocclude a given physiological opening. The balloon may also havemultiple segments of similar or different shapes that can beindependently inflated to accommodate different physiological openings.

Depending on the physiological opening intended for closure and theability of the balloon to remain immobilized adequately by its shape, anadditional support mechanism may be incorporated. This mechanism may bea thread, shaft, or tube that remains attached to the balloon and/orpatch and extends to or beyond the percutaneous opening by which accesswas gained to the subcutaneous tissue/space or to the circulatorysystem. The extension may then be actively attached to the surroundingtissue. Said attachment may be accomplished through suturing and/orthrough the use of a secondary piece of material (anchor) that can beembedded into the surrounding tissue. This attachment should hold theextension in tension or compression in order to adequately immobilizethe balloon onto the physiological opening.

Referring now to FIGS. 8 through 10, in one embodiment, the device iscomprised of a balloon catheter and the mounted patch 9. A biodegradablethread 10 is attached to the balloon/patch and extends in the directionof the balloon catheter. The catheter portion 11 of the balloon catheteris independent and fits into a hole, in the form of a neck 12, on oneend of the balloon 13. The balloon is held in place over the catheter byan elastic material in tension 14, which covers a portion of the neck.Depending on the thickness of the catheter, a metal stylet may beinserted into the catheter to provide support during implantation. Forimplantation, the balloon mounted patch is first placed into a shortby-pass sheath. It is then introduced through the hemostat valve of along sheath, which is already implanted in the patient's vasculature,and is advanced to the appropriate physiological opening. If a metalstylet was used, it is removed, and the balloon is inflated andpositioned at the site of the physiological opening. Once correctplacement has been verified, the catheter is pulled out of the balloon,and the remaining tension of the elastic piece automatically seals theneck (synching) 15, preventing balloon deflation. The introducing sheathis then pulled over the extending biodegradable thread and is removedfrom the vasculature. The biodegradable thread, which extends outside ofthe percutaneous entry point, is pulled to ensure immobilization of theballoon/patch and it is sutured beneath the skin.

A simple improvement of this embodiment can be made by using an anchorcomprising a small piece of relatively rigid material 16 with a centralshaft 17, through which the thread can be passed, intended to facilitateor circumvent the suturing process. This piece can be made frombiodegradable materials. Such an anchor would hold the thread intension, either by wrapping the thread around it and/or by forming aknot and/or by a clamping mechanism. The material would then be safelyembedded under the skin.

In yet another embodiment, the same setup as the previous embodiment isused with the exception of a screw mechanism instead of a synchingmechanism connecting the two pieces of the balloon catheter. In additionto the screw mechanism, a one-way valve is incorporated in the balloonto prevent balloon deflation after the catheter has been detached. Allmaterials comprising the screw mechanism and one-way valve arepreferably biodegradable.

In another embodiment, the device is comprised of a balloon catheter andthe mounted patch. The catheter is made from a biodegradable materialand it is permanently attached to the catheter. Depending on thethickness of the catheter, a metal stylet may be inserted into thecatheter to provide support during implantation. For implantation, theballoon mounted patch is first placed into a short by-pass sheath. It isthen introduced through the hemostat valve of a long sheath, which isalready implanted in the patient, and is advanced to the appropriatephysiological opening. If a metal stylet was used, it is removed, andthe balloon is inflated and a positioned on or about the physiologicalopening. Once correct placement has been verified, the introducingsheath is pulled over the balloon catheter and is removed from thepatient. The portion of the catheter that extends outside of thepercutaneous opening can then be capped to prevent balloon deflation,and a optionally a secondary piece can be advanced over the catheter andembedded under the skin to act as an anchor. Such an anchor piece wouldbe attached to the catheter by a ratchet, screw, or clamping mechanismand it should hold the balloon catheter in tension or compression tomaintain the balloon/patch immobile on the physiological opening.

At least one embodiment of the invention has been described hereinsolely for the purposes of illustrating the invention in its variousaspects. It is contemplated and to be explicitly understood that varioussubstitutions, alterations, and/or modifications, including but notlimited to any such implementation variants and options as may have beenspecifically noted or suggested herein, including inclusion oftechnological enhancements to any particular method step or systemcomponent discovered or developed subsequent to the date of thisdisclosure, may be made to the disclosed embodiments of the inventionwithout necessarily departing from the technical and legal scope of theinvention as defined in the following claims.

1. A method of placing a patch at the site of a physiological opening comprising: (a) providing a patch of a polymeric material having an adhesive applied to an outer portion thereof; (b) placing said patch on an uninflated distal balloon; (c) placing said patch and said balloon proximate to the physiological opening; (d) inflating said balloon; (e) forcing said balloon and said patch firmly against the physiological opening; and (f) deflating and removing said balloon leaving said patch affixed to said physiological opening.
 2. A method in accordance with claim 1, wherein said adhesive applied to said patch is in an inactive form.
 3. A method in accordance with claim 2, further comprising activation of said adhesive prior to said step (f) of deflating and removing said balloon.
 4. A method in accordance with claim 2, wherein said adhesive is a two-stage adhesive with a transition that is sensitive to pH.
 5. A method in accordance with claim 2, further comprising injecting an adhesive initiator around said physiological opening prior to said step (e) of forcing said balloon and said patch firmly against the physiological opening.
 6. A method in accordance with claim 3, wherein said step of activating said adhesive comprises applying electromagnetic energy to said adhesive.
 7. A method in accordance with claim 6, wherein said electromagnetic energy comprises radiation in a group consisting of the ultraviolet, visible, and infrared spectrums.
 8. A method in accordance with claim 3, wherein said step of activating said adhesive comprises exposing said adhesive to ambient or applied thermal energy.
 9. A method of placing a patch at the site of a physiological opening comprising: (a) providing a patch of a polymeric material placed on an uninflated distal balloon to create a balloon/patch assembly; (b) providing a catheter, detachably coupled to said balloon; (c) utilizing said catheter to place said patch and said balloon proximate to the physiological opening; (d) inflating said balloon to bring said balloon/patch assembly in contact with said physiological opening; and (e) detaching said catheter from said inflated balloon/patch assembly and withdrawing said catheter.
 10. A method in accordance with claim 9, further comprising: (f) deflating said balloon following a coagulation/endothelialization period.
 11. A method in accordance with claim 9, further comprising: (f) providing an elongate support mechanism for immobilizing said balloon/patch assembly following step (e) of detachment of said catheter.
 12. A method in accordance with claim 11, wherein said support mechanism comprises a thread extending from said balloon/patch assembly to percutaneous opening.
 13. A method in accordance with claim 11, further comprising: (g) attaching a proximal end of said support mechanism to tissue surrounding said percutaneous opening.
 14. A method in accordance with claim 13, further comprising an anchor for attachment of said proximal end of said support mechanism to said percutaneous opening.
 15. An occlusive device for placement about a physiological opening, comprising: a catheter having a proximal and a distal end; a distal uninflated balloon in said catheter adjacent said distal end thereof; an inflation tube extending in said catheter from said balloon to and beyond said proximal end; a patch of polymeric material at least partially surrounding said balloon; and an adhesive applied to said patch.
 16. A device in accordance with claim 14, wherein said adhesive is inactive.
 17. An occlusive device for placement about a physiological opening, comprising: a catheter having a proximal and a distal end; a distal uninflated balloon, detachably coupled to said sheath; an polymeric patch disposed over said uninflated balloon to form a balloon/patch assembly; at least one elastic element for preventing deflation of said balloon upon inflation of said balloon and detachment of said catheter.
 18. An occlusive device in accordance with claim 17, further comprising: an elongate supporting mechanism, coupled to said balloon/patch assembly, for maintaining placement of said balloon/patch assembly proximate to said physiological opening.
 19. An occlusive device in accordance with claim 18, further comprising: an anchor, for securing a proximal end of said elongate supporting mechanism in a percutaneous opening. 